Vehicles with an Internal Combustion Engine (ICE) include an exhaust gas treatment system for reducing the toxicity of the exhaust gas from the engine. The treatment system typically includes at least one and often multiple catalytic devices. If the engine includes a diesel engine, then the catalytic devices may include, for example, one or more of a diesel particulate filter, a diesel oxidation catalyst, a catalytic converter, and/or a selective catalytic reduction device. Each of the catalytic devices includes a catalyst that reduces nitrogen oxides in the exhaust gas to nitrogen and carbon dioxide or water, as well as oxidizes carbon monoxide (CO) and unburnt hydrocarbons (HCs) to carbon dioxide and water. The catalyst may include, but is not limited to, Platinum Group Metals (PGM). The catalyst must be heated to a light-off temperature of the catalyst before the catalyst becomes operational. Accordingly, the exhaust gas must heat the catalyst to the light-off temperature before the reaction between the catalyst and the exhaust gas begins. The catalyst may be intentionally heated to the light-off temperature during a regeneration process to burn off the accumulated hydrocarbons.
In order to determine when to regenerate the exhaust gas treatment system, the vehicle may use a model to predict when the catalytic device(s) are required to be regenerated. The model provides an estimation of the accumulated hydrocarbons in the catalytic device, based on one or more actual operating conditions of the vehicle. The operation of the engine may be controlled to heat the catalyst to the light-off temperature, to regenerate the catalytic device(s), based on the estimated hydrocarbon accumulation or storage from the model.